There was no particular purpose in this conferencing. But somehow it was comforting at this time for Earth’s scattered children to keep in touch. And so the links were left open, and to hell with the bandwidth.
Athena coughed softly, an attention-alerting tic she had picked up from Aristotle. “Excuse me, Bud.”
“What is it, Athena?”
“I’m sorry to disturb you. It’s just that the shadowing is almost complete. I thought you might want to see the Earth …”
On his biggest display softscreen she brought up an image of the home planet. But Earth’s face was dimmed. Bud looked into a tunnel of shadow millions of kilometers long, a shadow cast over both Earth and Moon—and cast by a human construction. Bud had seen simulations of this event a hundred times. But even so he was awed.
The silence was broken by Athena. “Bud?”
“Yes, Athena?”
“What are you thinking?”
He had learned to be cautious in his responses to her. “I’m overwhelmed,” he said. “I’m stunned by the scale of what we’ve done.” She didn’t reply, and he said at random, “I’m very proud.”
“We did well, didn’t we, Bud?”
He thought he detected a note of longing in her voice. He tried to figure out what she wanted him to say. “We did. And we couldn’t have done it without you, Athena.”
“Are you proud of me, Bud?”
“You know I am.”
“But I like to hear you say it.”
“I’m proud of you, Athena.”
She fell silent, and he held his breath.
The great task of turning the shield had taken months, and Bud was very glad it was over.
The shield had been purposefully built edge-on to the sun, so that during the years of construction only a fraction of Earth’s light would be occluded: after all, crops still had to be grown. But now the day of trial was approaching, and the shield had to be pivoted so that its face, seen from Earth, lay square across the sun. That trivial-sounding maneuver had been a challenge to compare with any they had faced during the construction process.
The shield was thirteen thousand kilometers across, but it was a thing of glass splinters and spun-out foam, scarcely a solid object at alclass="underline" you could put your fist through it without even noticing. The lightness had been necessary; otherwise the beast could never have been constructed at all. But that extraordinary lightness of structure made the shield almost impossible to maneuver.
It wasn’t as if you could just burn the attitude thrusters on Aurora2 and haul the whole thing around. If you tried that, the big old ship would just rip itself out of the gossamer web in which it was embedded. And so delicate was the structure that applying excessive pressure anywhere across the face of the disk could easily result in rips, not tilting. What made it still more difficult was that the shield was rotating. The gentle centrifugal force kept the spiderweb structure from falling in on itself. But now the spin was a pain in the butt, because if you tried to tilt the shield it would fight against you like a gyroscope.
The only way to turn the shield was to apply a turning force gently, and carefully, and to distribute it across the disk’s surface so no one area came under too much pressure. The whole thing was dynamic, with the disk’s moments of inertia subtly changing at each moment; computationally it was an immense problem.
The only way to solve it, of course, was to give the job to Athena, the artificially-sentient soul of the shield. To her the shield was her body, its sensors and comms links her nervous system, its tiny motors her muscles. And she was so smart that the complicated task of tipping the disk was nothing but a vigorous mental workout.
So the months-long task had been carried out. By day and night constellations of tiny thrusters sparkled and fired in waves across the face of the disk, their patterns entrancing. Their tiny impulses gently but persistently nudged the disk.
And gradually, just as the simulations had predicted, the shield had tipped up to face the sun.
Bud knew he shouldn’t have worried so much. Everything had been planned out and simulated over and over; there was really very little room for failure. But he had worried even so. It wasn’t just the inherent risk of the maneuver, and not even an astronaut’s usual pious hope that if a screwup occurred, it wouldn’t be down to him.
There was something else that troubled him, something he couldn’t quite put his finger on. Something about Athena.
This third cybernetic Legal Person (Nonhuman) seemed to Bud to be quite unlike Aristotle and Thales, her older brothers. Oh, she was just as smart, efficient, and competent as either of them, maybe even smarter. But where Aristotle was always rather grave, and Thales a bit blunt and obvious, Athena was—different. She could be playful. Crack jokes. Sometimes she almost seemed skittish. Flirtatious! And at other times she seemed needy, as if her mental state depended on every word of praise he gave her.
He’d tried to discuss this with Siobhan. She just said he was an unreconstructed old sexist: Athena had a female name and voice, and so he had attached to her all his erroneous images of femaleness.
Well, maybe so. But he worked more closely with Athena than anybody else. And even though nobody else recognized it, and even though all the diagnostic routines showed she was clear, there was something about her that troubled him.
Once he even had the distinct impression Athena was lying to him. He challenged her directly—it went against all her programming—and of course she had denied it. And what could she possibly have to lie about? But the seed of doubt remained.
Athena’s “mind” was a logical structure every bit as complex as the physical engineering that comprised her, with nested layers of control reaching all the way from one-line subroutines that controlled her pinprick rocket thrusters to the grand cognitive centers at the surface of her artificial consciousness. The check routines didn’t pick anything up, but that might just indicate there was some deep and subtle flaw buried deep in that vast new mind, a flaw he didn’t understand, and whose cause he couldn’t diagnose. If there was something wrong he was stumped to know what he could do about it.
Anyhow Athena had performed this tilting maneuver, her first big challenge, perfectly, despite all Bud’s fretting. She could be as nutty as a fruitcake as long as she did her job just as well tomorrow. But he knew he wouldn’t relax until the work was done, one way or another.
On Bud’s softscreen the artificial eclipse was almost perfect now. Earth was almost entirely darkened, the shapes of its continents illuminated by strings of city lights along the coasts and the great river valleys. Only the thinnest crescent of daylight still shone at the planet’s limb. The Moon was in the image too, swimming into the shield’s Olympian shadow. As it happened, right now the Moon’s orbit had brought it close to the Earth—sun line, in anticipation of the total eclipse it would cast tomorrow.
“My God.” Mikhail spoke from Clavius. “What have we done?”
Bud knew what he meant. The surge of pride he had expected at this moment, as the shield was finally completed and positioned, the culmination of years of heroic labor, was quickly dissipated by the meaning of this vast celestial choreography. “It really is going to happen, isn’t it?”
“I’m afraid so,” Mikhail said sadly. “And we few are stuck out here.”
“But at least we have each other,” Helena said, on Mars, some minutes later. “It’s a time to pray, don’t you think? Or sing, maybe. It’s a shame no decent hymns have been written for spacegoers.”